/*
 * Copyright (C) 2008 TranceCode Software
 *
 * This library is free software; you can redistribute it and/or modify it under
 * the terms of the GNU Lesser General Public License as published by the Free
 * Software Foundation; either version 2.1 of the License, or (at your option)
 * any later version.
 * 
 * This library is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
 * details.
 * 
 * You should have received a copy of the GNU Lesser General Public License
 * along with this library; if not, write to the Free Software Foundation, Inc.,
 * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 
 *
 * $Id$
 */
package org.trancecode.rdf;

import org.trancecode.core.AbstractImmutableObject;

import com.google.common.base.Preconditions;
import com.google.common.base.Predicate;
import com.google.common.base.Predicates;


/**
 * Utility methods related to {@link ValueFilter}.
 * 
 * @author Herve Quiroz
 * @version $Revision: 3842 $
 */
public final class ValueFilters
{
	private static final ValueFilter any = fromPredicate(anyValuePredicate());


	private ValueFilters()
	{
		// No instantiation
	}


	public static Predicate<Value> anyValuePredicate()
	{
		return Predicates.alwaysTrue();
	}


	public static ValueFilter any()
	{
		return any;
	}


	public static ValueFilter fromPredicate(final Predicate<Value> predicate)
	{
		return new PredicateValueFilter(predicate);
	}


	private static class PredicateValueFilter extends AbstractImmutableObject implements ValueFilter
	{
		private final Predicate<Value> predicate;


		public PredicateValueFilter(final Predicate<Value> predicate)
		{
			super(predicate);
			Preconditions.checkNotNull(predicate);
			this.predicate = predicate;
		}


		@Override
		public boolean matches(final Value value)
		{
			return predicate.apply(value);
		}
	}
}
